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Weld Quality
WeldingQualification
&Certification
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.ecture 14 p1
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Lecture ~3cope
Need for welding qualification Codes & standards requirements
- Welding procedure specifications- Welding procedure qualification- Welding operator qualification
Company certification
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Need IFor Weld Qualification
Many variables influence weld quality, related tothe parts to be joined, the welding process andwelding operator skill
The purpose of qualification is to demonstratethat welding procedures and personnel areadequately controlled and are capable ofacceptable results
Such tests cannot foretell performance inproduc::tion. Quality of the production weldsshould be determined by inspection during andafter the actual welding.
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Lecture 14
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Codes & Standards
Application codes & standards that specifyqualification requirements for weldinginclude:- ASME Boiler and Pressure Vessel Code
=~~~ ~~11 ~:~:~~i:e~~~~Code ill~.~lft- API 1104 Standard for Welding Pipelines and Related
Facilities- eSA W59 Standard for Welded Steel Construction
Standards for weld qualification- AWS B2.1 Wt~lding Procedure and Performance
Qualification
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14 p4
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lecture 14
Codes & Standards Requirements
A common approach to qualify weldingprocedures is by preparation and testing ofstandard test pieces. The qualification testsneed not be repeated unless the weldingprocedure specification is changed.
Some' pressure vessel standards require testplates to be welded at the same time as thevessel seams and subsequently tested.
Other standards accept certain weldingprocedures as "prequalified"
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Welding I)rocedure Specification Standards normally require the contractor to
prepare and qualify Welding ProcedureSpecifications (WPS)
A WPS should define the welding variables insufficient detail to ensure that the requiredquality is met
Standards differ with respect to the generalityor specificity of WPS- Some standards are very specific in defining the content
of a WPS e.g. ASME Section IX. Other standards aremore general
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Welding Procedure Specifications-
Typical VVPS Contents
scope Base metal
to simplify qualifications,standards often group basemetals by similar composition orstreng1h levels
Welding process Filler metal Type of current and range Arc voltage Travel speed Heat input
Joint preparation _ Welding details Welding positions Preheat & interpass
temperatures Post weld heat treatment
and finishing
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lecture 14 p7
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,14
ASME Salmple WPS
p8
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QW-482 1992 SECI10N IX
QW~Z SUGGI5STED FORMAT FOR WELDING PROCEDURE SPECIFICATIONS (wPSI(See ClW.zOO.1, Section IX. ASME Boller end P........V~ Code'
__ pmz INt: ... i.n- 24bifJ+___No wk Ol~ ..... (fj.to::!1 .if .... POR ....w Pi1R 01230_No Q ,...-~.fJ.....~.,r-------
_. " &11~. si?fii~ :1'>. " MANOAI...(All Mh ..................... I ...t
-- v- l.fl.OOViE.-----=--==.::......:....--.::r----_""11I,'--- ~t;!l,---__"'""' :-:-_,...~:!Il-=-=_:--_1'......__......-..10_ ONuc_......o Noe.,..-ue 0 OCher......... "'Oducdon~.......~_Wri_D (Pdue:..........................................................
lW" t' .... 101M ..... IN ....... of ...w .... ..., be
-lAo ...._ol __.. _ ..__........... ..,... MltIlllMd for fIIOIdl.......- ....._ .... 1
'BASE METAUI_' ,..... I _ .... --.!'--_,
Oft SAIe 'flwdoli type"" --.;;:,;,~ :.r....:::;l~-;:l'----'.lpecifiwdo" tYPe '......=-" aL-"fL-...........__-'
Oft-... ..... ....J
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--, Gtoc"'---T~==....__, GnIa..,_...J:I.!do=---,
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'FILLER METAU.-l c'",, , 00 I? 'A .... I...... No.lSFAI _:>"M~~~",::;;:A.6=--!__i;..,.~ +- _AM No. (CloooI " - 2..NAuI~=-...:I...L..2-=_r_--"'RJcM~-'"'lI'
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NONMANQA~AI'Pl!NDIX A QW-482
QW-4812 ee.tclo cOn..~
POSTWELD HEATTREATME~ ~071T............ _ "'or-Il"""EEo:=...-------ro.. _ N ..t:AL- _
POSITIONSI_I 5 ,._Co... a-_--='iJ"'1.J. ~werding PwOQiellion: Up,---,Xc-_PoII.ionCllof Fillet . I- -l
(Percent Compolit'on
G_al {Mixture' Ftow RIlle
ShtefdingTr.UingBacking
ELECTRICAL CHARACTERISTICSfO~tem.nt ACo< DC $"- Rc=.U)~"ily _
~ fRMtel .... Val. (R....t _IAmpf Hd voIli range Ihoufd be hlCOrdMl for MCh "ect:rode ,il.,PQIitioft. lind thick....... nc. ,",it tnf,Jtmltion INY be ..... in -. gb-.... form 1kniI. to ttult shown belo-.I
T....... EJ_ ........ T...._~W7U-'L {fhJS ~.. IIPu,. T
..- T' '0< GMAW__N==-'A:..:.. =-_-'-.. Wi _' ",fA
1------------.---------1 GAS lOW......
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layet'(sl
FiU., Metal
o~.Ty.......,.
CurrentOl"~
le.g., .Remarks. Com-ments. Hot Wire
Addition. Techntque.TOtc" Angle. Etc.!
t-'2. lo-,S;.1-u""N($.ll-l~ _.
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WPS Clualification
The pu rpose of qualification is to show thatweldin!~ in accordance with the WPS will-produce sound welds with adequate
proper1~ies. The WPS qualification requirements are
specifil:!d by the applicable standard. Qualification may be achieved by:
1. Use of prequalified welding procedures2. Qualification tests3. Mock-up tests
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Lecture 14 p9
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WPS Qualification
Prequalified welding procedures- The concept of prequalification is based on the reliability
of certain provl~n procedures as defined by the code orstandard (e.g. GSA W59, AWS 01.1)
- The contractor is nevertheless required to prepare WPSdocuments and to accept responsibility for their use.
- Any deviation from the standard negates the prequalifiedstatus
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e 14 P 10
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lecture 14
WPS Clualification Prequalified weldinq procedures
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Qualification tests- Qualifk~ation tests are intended to demonstrate that the
weldin!~ procedure results in sound welds with acceptablemechanical properties
- Tests need not simulate the actual conditions for a givenjob. They usually consist of conventional butt joints onplates or pipes
- Base 2lnd filler materials, welding variables and heattreatml~ntsmust follow production plans within specifiedranges.
- However, other variables such as joint geometry orweldin!~ position might not be considered as qualificationvariables
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-------- -------------------,1-----WPS QUcllification
Prequalified welding procedures Qualification tests Mock-up te:sts
- Mock-up tests are intended to simulate actual productionor field conditions.
- Codes and standards do not require preparation ofwelded mock-ups
- However, mc,ck-ups can help to anticipate or avoidproblems in production. They are also useful when difficultaccess or other practical considerations may influenceresults in-situ, such as repair welding of nuclear plants.
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I Tests elf Qualification Welds Specimens are removed from the sample
welds for examination and testing The type and number of tests depend on the
require!ments of the particular standard Commonly specified tests include:
- tensile tests- guided bend tests- Charpy notch toughness tests, or other fracture
toughness tests such as drop weight tests- macro-etch tests- non-de,structive examination
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Lec:ture 14 p13
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Mechanic:al Test Specimens (
TRANSVERSESPECIMEN
LONGITUDINAL WELDSPECIMEN
MINATURE ROUNDSPECIMENS DEPENDING ON T
IDENTICALDIMENSIONS
CHARPY.~~
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Face 8~ Root Bend Tests
WELD JOINT
FACE BEND
~~~~ROOT BEND~ SIDE BEND
Lecture 14 P 15
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Guided Bend Test Jigs....,....-.:rt:r
sHClULDEflS OR -t.:t>tAROU.2lS nIR.~+ Itt Imlt\.. .. .. ,
2A+lfT-I/" lnJI1Jij~
r $PEQMEN THICKNESS
T SPECIMEN THIQ(NESS(I) WnII11-ArouM '-I TeIt Jig
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e 14 P 16
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ICharp:v Impact Specimen
~C--/.\..-....-_-_-_----11~I-- 1.0112 in. :::::.J II (27.1; mm) I--2.165 in. (55 mm)--I
I~~-~----_.- -----
~I I~D+r0.394 in. I I . L0.394 in.(10 mml r--i0.079 In. (10 )12 mm) mm
~: 0.010 in.IO.2M mm)
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Lecture 14
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,------Recordin!~ Test Results
The we1dinn conditions and the test results areentered on a Procedure Qualification Record(PQR)
If the test re~sults meet the requirements of thestandard, the PQR is certified by the contractorand the third-party inspector
The WPS may then be issued for production
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ASME Sample PQR
Lecture 14 P 19
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QW-483 1992 SEC110N IX
QW-483 SUGGESTED F(IRMAT FOR PROCEQU"E Ql.IAUFlc;ATlON RECORD WQR)(SH QW-200.2. flection IX. ASME BciIIer end P_,. V..... COde)
R-..d Ac:tue1 Conditions UMd to Weld Teat Coupon.
"""'-''''''' Ae. c- .1,-.1 L -d-j----n.....-..........----" ...... OuaIoficot_ R..... No.~B: )12 A D...--=t..../..:-_(uV"'-"'-'5=
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NONMANDATORY APPENDIX A
QW-483 (Back)
QW-483
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Splc'menNo.
-T-
T...T--. '-
erat Ex-., Mils
IIr:.S'btJc; I LLL rlJiW~1f.i{.Manufacturer ...:.. _
____No _M......-ll...... . _
OtherT....NI'IAT_ ofT... __-=.:::..J.1:01- _
--0Ihe. _
6t.., . I f). ~I .Dote By _COeIaiI of reccHd of ........ illustrMive only and fNy be modified to conform to the iype and number of tescs required by the Code.'
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Changes in a qualified WPS
If a WPS is to be revised or modified beyondthe qualified ranges of the "essential variables"it is necessary to do additional qualificationtests
If the changE~s are within the qualified ranges ofessential variables, then a revised WPS can beissued without requalification
A PQR may support several WPS Since the PQR is a certified record of a
qualification test, it should not be revised.
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Welder Performance Qualification
WeJder or welding operator qualification testsare per1formed to determine the ability of thepersons tested to produce acceptable welds
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Lecture 14 p21
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Performance Qualification Req'ts
Most standards require each welder or weldingoperator to make one or more test welds inplate or pipe
Variables that affect the ability of welders tomake sound welds are considered qualificationvariables. These include:- welding proc:ess- filler metal- welding position- joint detail- plate thicknElss- welding tech nique
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Standard Welding Positions - Plates
Te,st Position 1G Test Position 2G
Te!;t Position 3G
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Test Position 4G
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Lecture 14 p23
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Welding Positions-Pipes (
~~.-t;2J.J-.l16.
Tellt Position 1G
Test Position 2G
Test Position 6G
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Perforrnance Qualification Tests Test spl3cimens may be groove welds or fillet
welds- groove weld qualification usually qualifies the operator to
weld bClth groove and fillet welds- fillet weld qualification limits the welder to fillet welds in
only thEI position qualified or less difficult positions
Tests consist of either bend tests, macro-etchtests or radiography
The weIder who prepares a test plate for aprocedure qualification is usually qualifiedwithin the variables in the WPS.
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lecture 14
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Performan~::e Qualification Records
Responsibility for performance qualificationrecords lies with the employer
After succe8sful qualification of a welder theemployer and third party inspector certify the
performancE~ qualification record. Most codes limit the duration of qualification to
three to six months inactivity For most codes qualification may be extended
indefinitely provided the welder performssatisfactory work within the stated period
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Lecture 14
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CompClny Certification
Some standards extend qualification to thecompany's organisational practices- ASME Boiler and Pressure Vessel Code
requirE~ audit by ASME of a company's quality control programbefore issuing a code symbol stamp for construction ofcompcnents
Sectiol1 III for nuclear components requires a quality assuranceprogram
-CSA WS9/W47.1 requims employment of designated welding engineers and
welding supervisors, and preparation of welding standards andWPS uudited by Canadian Welding Bureau
-ISO 9000 generalized quality assurance program
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Welding Qualification & CertificationLecture ScopeNeed for Weld QualificationCodes & StandardsCodes & Standards RequirementsWelding Procedure Specificationcont'dASME Sample WPSWPS Qulaificationcont'dcont'dcont'dTests of Qualification WeldsMechanical Test SpecimensFace & Root Bend TestsGuided Bend Test JigsCharpy Impact SpecimenRecording Test ResultsASME Sample PQRChanges in a Qualified WPSWelder Performance QualificationPerformance Qualification Req'tsStandard Welding Positions - PlatesWelding Positions-PipesPerformance Qualification TestsPerformance Qualification RecordsCompany Certification